1. Field of Invention
This invention relates to safety devices for motor vehicles and more particularly to safety devices for preventing the operation of the vehicle if the driver is in an unfit condition to drive.
2. Prior Art
There already exists in the prior art devices which discriminate the fitness of the driver's condition for driving and make it impossible to operate the motor vehicle if the driver is unfit. These devices are constructed to give the operator certain test exerciese and allow the operator to start the engine of the motor vehicle only if the driver makes appropriate responses to the exercises. Examples of this type of motion preventing device are those which prevent drunken driving or driving when too fatigued.
There also exists in the prior art other devices which necessitate having the seat belt fastened. These types of devices allow the operator to start the engine of the motor vehicle only when the driver has correctly responded to test exercises or when the seat belt is fastened. It is generally accepted that such devices are very effective in preventing accidents. Generally, these existing motion preventing devices operate by having a locking device on the ignition system such that the lock is released if the operator of the motor vehicle is in a suitable condition. The problem with these devices is that until the condition of the driver is ascertained, the engine of the motor vehicle cannot be started. This becomes a significant shortcoming especially in cold weather when driving with a warmed-up engine is necessary. In other words, the problem of lost operability of the car has arisen because the engine cannot be started until the driver's condition has been found acceptable or the seat belt has been fastened. Or in other words, while the testing of the driver's condition is being carried out the engine cannot be started which in turn lengthens the time until the engine is warmed up and can be driven, all to the annoyance of the operator of the motor vehicle. Another difficulty is with systems where the belt must be fastened or the engine cannot be started, the driver of the motor vehicle cannot leave his seat during warmup.
Accordingly, it is an object of the present invention to provide a motion preventing device which overcomes the shortcomings of the prior art.